Automated discovery of monitoring devices on a network

ABSTRACT

A system and method are disclosed for the automated discovery of devices on a network, such as a TCP/IP network using Dynamic Host Configuration Protocol (“DHCP”) and Domain Name System (“DNS”) servers. Devices on the network may be discovered, identified, and tracked by a monitoring server. Communications with the monitoring server may include identification information for each device. The identification information may be stored in DHCP option fields, transmitted with DHCP messages, and used to identify whether the device is new to the network.

BACKGROUND

As network demands have increased, the management of devices connectedin a network has grown more complex. For example, managing devices on anEthernet network can be a complex and time consuming task. A networkusing dynamic allocation of internet protocol (“IP”) addresses fordevices may result in difficulties in discovering, identifying, andmanaging those devices because of the changes to the address. Inaddition, manual tracking and management of IP addresses assigned tocertain devices with static IP addresses may be difficult to coordinatewith devices using a dynamic address pool.

Devices may be configured to use the Dynamic Host Configuration Protocol(“DHCP”) to receive an IP address when connected to a network, butmonitoring of the devices may require reading the assigned address on alocal display and manually recording the address. Reassignment of IPaddresses or an expiration of an existing IP address may result in aloss of communications with the device until the device's new IP addressis obtained. It may be beneficial to improve the monitoring anddiscovery of devices in a network.

BRIEF DESCRIPTION OF THE DRAWINGS

The system and method may be better understood with reference to thefollowing drawings and description. Non-limiting and non-exhaustiveembodiments are described with reference to the following drawings. Thecomponents in the drawings are not necessarily to scale, emphasisinstead being placed upon illustrating the principles of the invention.In the drawings, like referenced numerals designate corresponding partsthroughout the different views.

FIG. 1 is an exemplary network management system;

FIG. 2 is an alternate embodiment of a network management system;

FIG. 3 is a process for automatically discovering devices on a network;

FIG. 4 is another alternate embodiment of a network management system;and

FIG. 5 is an alternative process for automatically discovering deviceson a network.

DETAILED DESCRIPTION

By way of introduction, the embodiments described below include a systemand method for automated discovery of devices on a network. Inparticular, devices on a TCP/IP network may be identified and tracked. Amonitoring server may discover devices using Dynamic Host ConfigurationProtocol (“DHCP”) and Domain Name System (“DNS”) servers. Devices mayacquire an Internet Protocol (“IP”) address and the monitoring servermay automatically discover the devices added to the network, as well asrecognizing when an IP address changes.

Other systems, methods, features and advantages will be, or will become,apparent to one with skill in the art upon examination of the followingfigures and detailed description. It is intended that all suchadditional systems, methods, features and advantages be included withinthis description, be within the scope of the invention, and be protectedby the following claims. Nothing in this section should be taken as alimitation on those claims. Further aspects and advantages are discussedbelow in conjunction with the embodiments.

FIG. 1 is an exemplary network management system 100. The networkmanagement system 100 includes a monitoring server 102, one or moredevices 112, a DHCP server 114, and a DNS master 116. The DNS master 116may also be referred to as a master DNS server. The monitoring server102 may operate to monitor or track the devices, such as the device 112,that are added to or existing on the network. Although not explicitlyshown, each of the components in the system 100 may be coupled throughone or more networks.

The network(s) that may connect any of the components in the networkmanagement system 100 to enable communication of data between thecomponents and devices may include wired networks, wireless networks, orcombinations thereof. The wireless network may be a cellular telephonenetwork, a network operating according to a standardized protocol suchas IEEE 802.11, 802.16, 802.20, published by the Institute of Electricaland Electronics Engineers, Inc., or WiMax network. Further, the networkmay be a public network, such as the Internet, a private network, suchas an intranet, or combinations thereof, and may utilize a variety ofnetworking protocols now available or later developed including, but notlimited to TCP/IP or other IP based networking protocols. The networkmay include one or more of a local area network (LAN), a wide areanetwork (WAN), a direct connection such as through a Universal SerialBus (USB) port, and the like, and may include the set of interconnectednetworks that make up the Internet. The network may include anycommunication method or employ any form of machine-readable media forcommunicating information from one device to another.

The DHCP 114 is a server that allows for the configuration andidentification of devices in an Internet Protocol (“IP”) network. Theremay be multiple DHCP servers in a given network as illustrated anddescribed with respect to FIG. 2. The DHCP server 114 may receiveadditional information about devices on the network (such as the device112) that can be used by the monitoring server 102 for tracking andmonitoring the devices that are connected to the network. In oneembodiment, the DHCP server 114 may be referred to as a dynamic networkaddress assignment server and be configured to allow for theconfiguration and identification of devices in any network.

DHCP is a network application protocol that may automate networkparameter assignment to devices, such as the device 112. New devicesthat are added to the network are assigned identification information byone of the DHCP servers. When the device 112 is connected to thenetwork, it requests information from the DHCP server 114. The DHCPserver 114 may manage a pool of IP addresses, as well as otherinformation and configuration parameters for each device connected inthe network, such as the device 112. The DHCP server 114 can assign anIP address to the device 112. The IP assignment may be based on a leasein which the IP address is valid for a certain length of time. The leasemay include an assignment of other IP parameters, such as a subnet maskand default gateway. During the lease, the IP address cannot be assignedto other devices. When the lease expires, the device can request a newlease and that IP address is available to other devices. Alternatively,the device may renew the lease prior to expiration.

The DHCP server 114 assigns an IP address to the device 112 before thedevice 112 communicates over the network. The DHCP server may allocateIP addresses through dynamic allocation, automatic allocation, staticallocation, manual allocation, or autoconfiguration. DHCP operations mayinclude IP discovery, IP lease offer, IP request, and IP leaseacknowledgement, which are further described with respect to FIG. 3. Thediscovery may include a DHCPDISCOVER command by which the device canbroadcast to find available servers and for receiving an IP address fromone of the available servers. A lease offer may include a DHCPOFFERcommand in which the DHCP server 114 reserves an IP address and offersan IP lease to the device 112. The offer may include additionalconfiguration information or options that may be sent to the device inaddition to the IP address includes a subnet mask, domain name, routerIP addresses, domain name server IP addresses, and static routes. Therequest may include a DHCPREQUEST command by which the device 112requests an IP address based on the offer from the DHCP server 114. Theacknowledgement may include a DHCPACK command by which the DHCP server114 acknowledges receiving the request for the IP address. Theacknowledgement may include the lease duration and other configurationinformation. DHCP operation is further described in “Networking DynamicHost Configuration Protocol,” IBM System i, Version 5 Release 4,published in February 2006, and hereby incorporated by reference.

When an IP address is assigned to the device 112, the DNS master 116 isupdated to associate a host or domain name with the device 112. The DNSmaster 116 comprises a computing device, such as a server, that providesa domain name (a.k.a. host name) to devices connected through thenetwork. The DNS master 116 may be one or more name servers. In analternative embodiment, the DNS master 116 may be referred to as adevice address translator and may be configured to translate a machinecomprehensible address for a device into a human comprehensible address.The human comprehensible address may be a host name or domain name. Inthe case of a DNS address translator, the machine comprehensible addresscorresponds to an IP address as discussed below.

The domain name system (“DNS”) translates the numerical identifiers(e.g. IP addresses) into human readable domain names. In particular, DNSis a distributed database system for managing host names and the IPaddresses associated with those host names. One server may maintain thehost names and associated IP addresses for a subset or zone. A zone maybe a portion or sub domain from a particular domain. A single domain maycomprise multiple zones for all of its host names and associated IPaddresses. There may be a single server for each zone, or a server maybe responsible for multiple domains and/or zones. A DNS server that hashost information and data for a particular zone is consideredauthoritative for the zone and can respond to queries about thedomains/hosts in its zone.

DNS may be used to assign a unique Fully Qualified Domain Name (FQDN) todevices on a network. As an example, a device may have a host name ofSN12345 and a FQDN of SN12345.company.com. Once the monitoring serverhas discovered a device on the network, it may map the FQDN of thedevice to an internal naming structure used to reference the device.Alternatively, the monitoring server may simply use the FQDN as theprimary reference for the device.

DNS resource records may record the mapping of IP addresses, domainnames, and the devices associated with them. The resource records mayprovide the IP address assigned to a particular domain name when the DNSserver receives a query from another source. DNS organization, queries,and resource records are further described in “DNS,” IBM eserveriSeries, Version 5 Release 3, published in August 2005, and which ishereby incorporated by reference.

The DHCP server may be configured to send update requests to the DNSserver whenever a new address is assigned. When a device using DHCPreceives an IP address, that data may be sent to the DNS server. DHCPmay be configured to update the resource records for the DNS system.When a device's address changes, DHCP can automatically send an updateto the DNS server so that device can be located at its new IP address.The device identification information may be sent to the DNS server andstored in the resource records.

The device 112 may be a computing device that connects with a network.Examples of a user device include, but are not limited to, a personalcomputer, personal digital assistant (“PDA”), cellular phone, or otherelectronic device. In one embodiment, the device 112 may be a monitoringdevice, such as an intelligent electronic device (“IED”) or a powermeter. Exemplary IED devices 112 include programmable logic controllers(“PLC's”), Remote Terminal Units (“RTU's”), electric/watt hour meters,protection relays and fault recorders as described below. The IED's maymake use of memory and microprocessors to provide increased versatilityand additional functionality. Such functionality includes the ability tocommunicate with remote computing systems, either via a directconnection, e.g. modem or via a network, such as the network system 100.For more detailed information regarding IED's capable of networkcommunication, please refer to U.S. Pat. No. 6,961,641, entitled“INTRA-DEVICE COMMUNICATIONS ARCHITECTURE FOR MANAGING ELECTRICAL POWERDISTRIBUTION AND CONSUMPTION”, U.S. Pat. No. 6,751,562, entitled“COMMUNICATIONS ARCHITECTURE FOR INTELLIGENT ELECTRONIC DEVICES”, andU.S. Pat. No. 7,216,043, entitled “PUSH COMMUNICATIONS ARCHITECTURE FORINTELLIGENT ELECTRONIC DEVICES,” each of which is hereby incorporated byreference.

IED's such as Programmable Logic Controllers (“PLC's”), Remote TerminalUnits (“RTU's”), electric power meters, protective relays, faultrecorders and other devices are coupled with power distribution networksto manage and control the distribution and consumption of electricalpower. Such devices typically utilize memory and microprocessorsexecuting software to implement the desired power management function.IED's include on-site devices coupled with particular loads or portionsof an electrical power distribution system and are used to monitor andmanage power generation, distribution and consumption. IED's may also bereferred to as power management devices (“PMD's”).

Although not shown, there may be multiple devices in addition to thedevice 112, present in the network system 100. Each device may beassigned a different IP address from the DHCP server 114 and assigned adifferent host name from the DNS master 116. The devices may beconnected over a network, such as the Internet or an Intranet, with theother components of the network system 100.

The device 112 and the DNS master 116 may be coupled with the monitoringserver 102. The monitoring server 102 and the DHCP server 114 may be asingle component. The monitoring server 102 may automatically discoverwhen new devices, such as the device 112, are added to the network. Thediscovery and identification of devices on the network by the monitoringserver 102 is further described with respect to FIG. 3 discussed below.The monitoring server 102 may include a processor 104, memory 106,software 108 and an interface 110.

The processor 104 in the monitoring server 102 may include a centralprocessing unit (CPU), a graphics processing unit (GPU), a digitalsignal processor (DSP) or other type of processing device. The processor104 may be one or more general processors, digital signal processors,application specific integrated circuits, field programmable gatearrays, servers, networks, digital circuits, analog circuits,combinations thereof, or other now known or later developed devices foranalyzing and processing data. The processor 104 may operate inconjunction with a software program, such as code generated manually(i.e., programmed).

The processor 104 may be coupled with a memory 106, or the memory 106may be a separate component. The interface 110 and/or the software 108may be stored in the memory 106. The memory 106 may include, but is notlimited to, computer readable storage media such as various types ofvolatile and non-volatile storage media, including random access memory,read-only memory, programmable read-only memory, electricallyprogrammable read-only memory, electrically erasable read-only memory,flash memory, magnetic tape or disk, optical media and the like. Thememory 106 may include a random access memory for the processor 104.Alternatively, the memory 106 may be separate from the processor 104,such as a cache memory of a processor, the system memory, or othermemory. The memory 106 may be an external storage device or database forstoring recorded ad or user data. Examples include a hard drive, compactdisc (“CD”), digital video disc (“DVD”), memory card, memory stick,floppy disc, universal serial bus (“USB”) memory device, or any otherdevice operative to store ad or user data. The memory 106 is operable tostore instructions executable by the processor 104. The functions, actsor tasks illustrated in the figures or described herein may be performedby the programmed processor executing the instructions stored in thememory 106. The functions, acts or tasks are independent of theparticular type of instruction set, storage media, processor orprocessing strategy and may be performed by software, hardware,integrated circuits, firm-ware, micro-code and the like, operating aloneor in combination. Likewise, processing strategies may includemultiprocessing, multitasking, parallel processing and the like. Theprocessor 104 is configured to execute the software 108.

The interface 110 may allow for communication with the device 112, theDHCP server 114, and/or the DNS master 116. In one embodiment, theinterface 110 may include a user interface configured to allow a userand/or administrator to interact with and configure the monitoringserver 102. Accordingly, the interface 110 may include a keyboard,keypad or a cursor control device, such as a mouse, or a joystick, touchscreen display, remote control or any other device operative to interactwith the monitoring server 102. The interface 110 may include a displaycoupled with the processor 104 and configured to display an output fromthe processor 104. The display may act as an interface for the user tosee the functioning of the processor 104, or as an interface with thesoftware 108 for providing input parameters

As described below with respect to FIG. 3, the monitoring server 102acts as a DNS slave that manages a domain name zone for certain deviceson the network. The monitoring server 102 automatically learns ofdevices that are added to or removed from the network based on theidentification information that it receives from each device. Theidentification information may be located in a DHCP option field, suchas the option 12 (host name) field or in the vender specific option(VSO) field. This information allows the monitoring server 102 to trackwhich devices are located on the network and to identify when a deviceis removed and when a device is added to the network. The identificationinformation provided from the DHCP server may be different than theidentification information used to identify devices.

When devices are added to the network, they are assigned an IP addressthat is associated with a name within a specific domain name zone (suchas company.com). When the monitoring server is first configured to finddevices attached to the network, it initiates a zone transfer from theDNS master server for the domain name zone associated with the devicesattached to the network. The monitoring server may then initiate anincremental zone transfer when notified of changes on the network by aNOTIFY message from the DNS master server. The monitoring server mayalso initiate a complete zone transfer for other reasons, including: 1)a loss of configuration information on the monitoring server; 2) a lossof communications with more than a predetermined number of devices; 3) aDNS server which does not support incremental transfers; and 4) anaddition of new monitoring zones.

Large network systems may use multiple monitoring servers, with eachserver responsible for some subset of devices in the system. DNS zonesmay be used to associate a subset of devices to a specific server. Forexample, the sub-domain bldg1.company.com may be associated with devicesand the monitoring server in a first building, while the sub-domainbldg2.company.com may be associated with devices and the monitoringserver in a second building. Devices may be assigned to a particularzone based on the structure of their IP address. For example, alldevices in the first building may have an IP address structure of10.168.85.3X. Alternately, devices may be assigned to a particular zonebased on identification information the devices provide in the DHCPoption fields (e.g., the VSO field).

FIG. 2 illustrates an alternate embodiment of a network managementsystem 200. The system includes the DNS master 116 and the device 112,as well as multiple DHCP servers 208, 210. The monitoring server 202 inthe network system 200 includes the DHCP server 114 (labeled DHCP (MS)in FIG. 2), and acts as a DNS slave 206. DHCP (MS) may indicate that theDHCP server is specialized for communication with the monitoring server(MS) while other DHCP servers may not be configured to analyze andinterpret additional identification information to the monitoringserver. As discussed below, FIG. 3 illustrates an exemplary processutilizing components from the network systems 100, 200.

The network system 200 illustrates multiple DHCP servers (DHCP1 208 andDHCP2 210) that communicate with the device 112. In one embodiment, theDHCP servers 208, 210 may be generic DHCP servers, while the DHCP server114 may be a specialized DHCP server that receives additionalidentification information about devices on the network that can be usedby the monitoring server 102 for tracking and monitoring the devicesthat are connected to the network. In one embodiment, the specializedDHCP server reads and interprets information in standard DHCP protocolfields that other DHCP servers may not know how to interpret. Asdiscussed, the additional information is identification information fromthe DHCP option fields that identifies the device. The DHCP server 114may be a specialized server that is specific to a certain network orspecific to a monitoring server, such as the monitoring server 102. Inalternative embodiments, the DHCP server 114 may be combined with othernon-specialized DHCP servers, such as servers 208, 210.

The monitoring server 202 may be combined with the DHCP server 114 as asingle component. Alternatively, as shown in FIG. 1, the DHCP server 114and the monitoring server 102 may be different components. Themonitoring server 202 may act as a DNS slave 206. In particular, the DNSmaster 116 sends a message to the DNS slaves to learn about changes indomains. Each of the devices on the network, such as the device 112, aswell as the monitoring server 202 may be DNS slaves. In one example,when the device 112 is a gateway for other devices and operating as aslave DNS server, the gateway may directly represent attached serialslave devices as separate devices on the network. The representation maybe within some sub-domain, such as “gateway.company.com”.

FIG. 3 is a process by which the monitoring server automaticallydiscovers devices on the network. The process described in FIG. 3 may beperformed by any of the embodiments shown in FIG. 1, 2, or 4. Inparticular, the process in FIG. 3 relates to interactions between adevice (e.g. device 112), a monitoring server (e.g. monitoring server102, 202), one or more DNS servers (e.g. DNS Master 116), and one ormore DHCP servers (e.g. DHCP 114).

In block 302, the device 112 makes a discovery broadcast. The discoverybroadcast may be a DHCPDISCOVER that is submitted to one or more DHCPservers. The broadcast may include identification information in thevendor-specific options (VSO) field (such as its serial number) that maybe used later by a DHCP server specific to the monitoring server. Thedevice may also use DHCP option fields—such as option 12 (host name)—forfurther identification. As described, the DHCP server may utilize thedevice identification information for discovering/identifying devicesthat are added to the network. When the hostname field is used for adevice ID, generic DHCP and DNS servers may be used by the monitoringserver to discover devices added to the network. When the VSO field isused for device ID, a generic DHCP server may need to be configured toprocess the VSO field (i.e. a DHCP server specific or specialized forthe monitoring server).

The DHCPDISCOVER broadcast may go to multiple DHCP servers. In responseto the DHCPDISCOVER broadcast, any of DHCP servers may offer to providea service (DHCPOFFER) in block 304. As shown in FIG. 1, the DHCP server114 may send a DHCPOFFER to the device 112. When multiple DHCP serversprovide an offer in response to a discover broadcast, the DHCP serverthat is specialized or configured to communicate with the monitoringserver may be chosen. In particular, the discover broadcast may includeadditional identification information that is identified by thespecialized DHCP server that is looking for the additionalidentification information. Accordingly, the DHCP server 114 may includeadditional features specific to the monitoring system and/or themonitoring server 102 that look for the identification information thatmay be associated with a device. The DHCP server 114 may look for theidentification information (such as in the VSO field) in DHCPDISCOVERbroadcast before making a DHCPOFFER to the device 112. The DHCP serverspecific to the monitoring server may use the VSO field in the DHCPOFFERmessage to identify itself to monitoring devices.

Upon receiving offers from one or more DHCP servers, the device 112 mayrequest an address with a DHCPREQUEST command in block 306. In oneembodiment, the device 112 may make a determination as to whether any ofthe DHCP servers are associated with the monitoring system. Asdescribed, the DHCP server 114 is associated with the monitoring server102. Accordingly, when the DHCP server 114 makes an offer to the device112, the device requests an address from that server rather than otherDHCP servers that are not associated with the monitoring system. A DHCPserver that is associated with the monitoring system may includeidentification information in its messages and the determination may bebased on an examination of the message to locate the identificationinformation. For example, the determination may be based on anexamination of the VSO field of the DHCPOFFER message received by thedevice 112 in response to its DHCPDISCOVER broadcast. Alternatively,another field or location may include identification data that isexamined from the DHCPOFFER message.

When the request is sent to the DHCP server, the DHCP sends anacknowledgement to the device as in block 308. In particular, the DHCPserver sends a DHCPACK command to the device and leases an IP address tothe device. The acknowledgement from the DHCP server acknowledges therequest from the device 112. The device may receive multiple offers frommultiple DHCP servers, but may then send a single request to the chosenDHCP server, which then acknowledges the request. The chosen DHCP servermay be the server that looks for and includes device identificationinformation in its messages.

After the acknowledgement, the DHCP server has leased an IP address tothe device. In block 310, the DHCP server then updates the DNS master116 with the address and sets up the host name for the device. Inparticular, address record (“A”) is updated in the DNS master 116 toreflect the host name for the device and the IP address for the device.The host name may be set up for the device based on the informationreceived. For example, the fully qualified name may be based on a serialnumber or a model type for the device, as well as the company domain.For example, the host name may be SN12345.company.com, where SN12345 isthe serial number for the device and the company's domain iscompany.com. Depending on the device, the DNS master 116 may also setthe TXT record for the device to include information received, such asthe serial number for the device. In one embodiment, the DNS SecurityExtensions (DNSSEC) may be used for this information exchange.

The DNS master may then send a notification command to any DNS slaves onthe network as in block 312. The notification command may be a NOTIFYmessage that prompts the DNS slaves on the network to initiate anincremental zone transfer and refresh the changes in the zones beingmanaged since the last zone transfer operation. When the master DNSserver receives an update from the DHCP server (including new device onthe network or devices with a changed IP address) it sends the NOTIFYcommand to slave DNS server(s) to let them know some change hasoccurred. The slave DNS servers can then request a transfer and receivethe updated data themselves. For example, master DNS server 116 mayreceive an update from DHCP server 114, prompting master DNS server 116to send a NOTIFY message. Upon receiving the NOTIFY message, slave DNSserver 206 may initiate an incremental zone transfer.

In addition to the zone transfer, a monitoring server may query a DNSserver directly and search for nodes or slaves with attributes unique tomonitoring devices on the network. Some DNS servers can be configured touse database systems (e.g., SQL Server or MySQL), and these databasesystems may offer interfaces for direct queries. The monitoring servermay search for domain names with a particular structure (e.g., all nodeswith a sub-domain of bldg1.company.com), or for specific strings in oneor more resource records (e.g., a TXT resource record identifying a nodeas particular type of device).

The monitoring server 102, 202 may act as a DNS slave within the networkas in block 314. The monitoring server 102, 202 is configured to managea domain name specific to certain devices on the network. For example,the monitoring server 102, 202 may be configured to manage themonitoring.company.com zone to learn of any devices added or removedfrom the network. The management of devices includes tracking the listof devices within the monitoring-specific sub-domain, and the creationof hostnames for devices. In one example, the monitoring server receivesID info for a new device from the DHCP VSO field (or DNS TXT record). Asthe authority for the “monitoring.company.com” sub-domain, the DNSserver on the monitoring server may create the FQDN“SN123.monitoring.company.com” for a device with serial number SN123.Alternately, when a gateway also contains a DNS server, it may performthe same task for serial slave devices attached to it.

In block 316, the monitoring server 102, 202 detects devices added tothe network and monitors devices removed from the network. In addition,the monitoring server 102, 202 has the information required to contact adevice that is added to the network. The monitoring server 102, 202 hasaccess to the IP address and host name for the device, as well as anyadditional information included in the TXT record for the device, suchas a serial number.

FIG. 4 is another alternate embodiment of a network management system400. In particular, the network system 400 illustrates a gateway orgateway device 402 within the network. The gateway 402 may couplemultiple slave devices, such as device1 404 and device2 406, to thenetwork. In alternative embodiments, each gateway may couple more orfewer slave devices to the network. A network may include multiplegateways coupling multiple slave devices to the network. As describedabove, the device 112 may be a gateway device with slave devices, or maybe a slave device connected to the network through a gateway.

Some devices may be operative to directly connect with a TCP/IP networkand directly support TCP/IP communications. Alternatively, certaindevices may only connect to a TCP/IP network through a gateway device.As shown, the gateway 402 may connect directly to the TCP/IP network andsupport one or more slave devices (devices 404, 406) communicating onthe TCP/IP network. For example, the gateway 402 may support the slavedevices 404, 406 on a serial communications bus (such as an RS-485serial bus). The gateway 402 may perform protocol translation betweenthe serial port to the slave devices 404, 406 and the TCP/IP network.The gateway 402 may facilitate automatic discovery by the monitoringserver 102 of slave devices attached to the gateway.

The gateway 402 may be identified in the VSO option field or anotherDHCP option field. The gateway 402 obtains an IP address and FQDN aswith other devices, but may include additional identificationinformation in one or more option fields. The information may simplysignal to the monitoring server 102 that the gateway 402 has one or moreslave devices 404, 406 attached to it. The monitoring server 102 canthen communicate with the gateway 402 directly to gather moreinformation about the attached slave devices 404, 406. Alternately, theadditional information may include identification information for eachattached slave devices 404, 406, such that the monitoring server 120 canbegin communications with each of the slave devices 404, 406 based onthe identification information provided by the gateway 402.

When the gateway 402 obtains an IP address and FQDN, it may registerwith the DNS master 116 as a slave DNS node. The gateway 402 may act asthe name server for any attached slave devices 404, 406, and may createa FQDN “alias” for each of the attached slave devices 404, 406. Forexample, the gateway 402 may obtain an IP address and FQDN ofgateway.company.com. The gateway 402 may then register with the DNSmaster 116 and create an FQDN alias for each of the slave devices 404,406, using a unique host name and FQDN ending in gateway.company.com.For example, a slave device with a serial number of SN12345 attached tothe gateway may have a FQDN of SN12345.gateway.company.com.

FIG. 5 is an alternative process for automatically discovering deviceson a network. The process described in FIG. 5 may be performed by any ofthe embodiments shown in FIG. 1, 2, or 4. A device connects to a networkand requests an IP address for identification. In block 502, the devicereceives an IP address for the network connection. The device thenprovides a DNS server with identification information in block 504. Theidentification information may include a device name, model, type,serial number, or other identifying label. The identificationinformation that is provided to the DNS server may be used foridentifying the device on the network. In particular, a monitoringserver queries the DNS server to determine the devices that areconnected as in block 506. The connected devices are identified based onthe identification information rather than their IP address. Themonitoring server may then compare the identified devices with a list ofpreviously known devices. The list of previously identified devices maybe updated with the newly identified devices in block 508. Themonitoring server can probe the newly discovered devices for theiridentification information as in block 510. In particular, theidentification information of the newly discovered devices may berecorded as part of the list of previously known devices. Accordingly,the next query of devices may identify those devices as previously knowneven if the IP address of the devices has changed.

A “computer-readable medium,” “machine readable medium,”“propagated-signal” medium, and/or “signal-bearing medium” may compriseany device that contains, stores, communicates, propagates, ortransports software for use by or in connection with an instructionexecutable system, apparatus, or device. The machine-readable medium mayselectively be, but not limited to, an electronic, magnetic, optical,electromagnetic, infrared, or semiconductor system, apparatus, device,or propagation medium. A non-exhaustive list of examples of amachine-readable medium would include: an electrical connection“electronic” having one or more wires, a portable magnetic or opticaldisk, a volatile memory such as a Random Access Memory “RAM”(electronic), a Read-Only Memory “ROM” (electronic), an ErasableProgrammable Read-Only Memory (EPROM or Flash memory) (electronic), oran optical fiber (optical). A machine-readable medium may also include atangible medium upon which software is printed, as the software may beelectronically stored as an image or in another format (e.g., through anoptical scan), then compiled, and/or interpreted or otherwise processed.The processed medium may then be stored in a computer and/or machinememory. The term “computer-readable medium” shall also include anymedium that is capable of storing, encoding or carrying a set ofinstructions for execution by a processor or that cause a computersystem to perform any one or more of the methods or operations disclosedherein.

The above disclosed subject matter is to be considered illustrative, andnot restrictive, and the appended claims are intended to cover all suchmodifications, enhancements, and other embodiments, which fall withinthe true spirit and scope of the present invention. Thus, to the maximumextent allowed by law, the scope of the present invention is to bedetermined by the broadest permissible interpretation of the followingclaims and their equivalents, and shall not be restricted or limited bythe foregoing detailed description. While various embodiments of theinvention have been described, it will be apparent to those of ordinaryskill in the art that many more embodiments and implementations arepossible within the scope of the invention. Accordingly, the inventionis not to be restricted except in light of the attached claims and theirequivalents.

1. A system for discovering devices on a network comprising: one or moredevices on the network that broadcast for access to the network, whereinthe broadcast includes identification information for the broadcastingdevice; a dynamic network address assignment server that receives thebroadcast and leases an address to the broadcasting device; a deviceaddress translator coupled with the dynamic network address assignmentserver that is updated with the leased address and assigns a host nameto the device; and a monitoring server communicating with the dynamicnetwork address assignment server that discovers devices on the networkbased on the identification information.
 2. The system of claim 1wherein the dynamic network address assignment server comprises adynamic host configuration protocol (DHCP) server and the device addresstranslator comprises a domain name system (DNS) server.
 3. The system ofclaim 2 wherein the network comprises a TCP/IP network and the addresscomprises an IP address.
 4. The system of claim 1 wherein leasing of theaddress further comprises: providing an offer message in response to thebroadcast; receiving a request from the device, wherein the device sendsthe request to the monitoring server after locating the identificationinformation; and providing an acknowledgement message acknowledging thelease of the IP address.
 5. The system of claim 4 wherein theidentification information is stored in an option field that is includedin the broadcast and the offer message.
 6. The system of claim 5 whereinthe option field comprises a Vendor Specific Option (VSO) field or anoption field for a host name.
 7. The system of claim 5 wherein theidentification information comprises a model, type, or serial number ofthe device.
 8. The system of claim 1 wherein the one or more devicescomprise intelligent electronic devices (IED's).
 9. The system of claim1 wherein one of the one or more devices comprises a gateway device thatconnects with other devices, and wherein the gateway device connectsthose other devices with the dynamic network address assignment serverand the device address translator.
 10. The system of claim 1 wherein theidentification information comprises an identification for the deviceand an identification for the dynamic network address assignment server.11. A system for monitoring devices on a network comprising: amonitoring server that includes dynamic host configuration protocol(DHCP) functions including leasing the devices an IP address, whereinthe monitoring server identifies the devices on the network based onidentification information from the devices; and a domain name system(DNS) server that is updated with the leased IP address from themonitoring server, and assigns a host name based on the leased IPaddress; wherein the monitoring server acts as a DNS slave that isprompted by the DNS server to monitor the devices on the network andidentify devices that are added or removed from the network based on theidentification information.
 12. The system of claim 11 wherein theleasing of the IP address comprises: receiving a DHCPDISCOVER broadcastfrom at least one of the monitoring devices requesting the IP address;providing a DHCPOFFER message to the broadcasting monitoring device;receiving a DHCPREQUEST from the monitoring device, wherein themonitoring device sends the DHCPREQUEST to the monitoring server afterlocating the identification information; and providing a DHCPACK messageacknowledging the lease of the IP address.
 13. The system of claim 11wherein the DNS server is updated to include the identificationinformation for each device as part of the TXT record of the device. 14.The system of claim 11 wherein the identification information for aparticular monitoring device is stored in a DHCP option field associatedwith that monitoring device.
 15. The system of claim 11 wherein the DNSserver prompting of the DNS slave comprises zone transfer.
 16. Thesystem of claim 14 wherein the DHCP option field comprises the VendorSpecific Option (VSO) field or the DHCP option field for a host name.17. The system of claim 11 wherein the identification informationoriginates as part of a zone transfer.
 18. A method for automatedmonitoring of devices on a network comprising: receiving a request froma device to join the network, wherein the request includesidentification information for the device; offering, upon receipt of therequest, to connect the device to the network; acknowledging theconnection of the device to the network; updating a device addresstranslator based on the identification information from the device forassociating a host name with the device; and updating a list of deviceson the network based on the identification information for the devices,wherein the list of devices on the network is used to identify theconnected devices and is compared with a prior list of devices todetermine which devices are newly connected.
 19. The method of claim 18further comprising: updating the list of devices on the network bycomparing the identification information for previously identifieddevices with the identification information for newly identified deviceson the network.
 20. The method of claim 18 wherein the offering toconnect comprises providing the device with a lease of an internetprotocol (IP) address for the network.
 21. The method of claim 18wherein the identification information comprises a model, type, orserial number of the device.
 22. A method for automated tracking ofdevices on a network by a monitoring server, the method comprising:receiving a discovery broadcast from a device; determining whether thediscovery broadcast includes identification information for thebroadcasting device; sending an offer to the device when the discoverybroadcast includes identification information; and utilizing theidentification information to track the devices on the network bymaintaining a list of devices on the network that includes theidentification information for each device.
 23. The method of claim 22wherein the determination includes checking DHCP option fields for theidentification information.